Incandescent lamp and projection device



Dec. 15, 1936. \\\`\B\B FORTNEY 2,064,252

INCANDESCENT LAMBQTEND PROJECTION DEVICE original Filehyly 5o, 1932 2 sheets-sheet 1 Dec. 15,1936. l B B FORTNEY 2,064,252

lN-CANDESCENT LAMP AND PROJECTION DEVICE` Original Filed July 50, 1932 2 Sheets'-Sheet 2 INVENTOR WORN/EY Patented Dec. l5, 1936 l' 1 UNITED STATES l'PAflENr OFFICE lircANnEscEN'r LAMP AND PROJECTION' DEVICE Brauddus Brock Fortney, Louisville, Ky.

Application July 30, 1932, Serial No. 626,783 Renewed October 10, 1935 2 Claims. (Cl. MII-41.3) This invention relates to projection apparaby controlling the character of projected light tus; more particularly, to projection apparatus rays. fOr use in CODDBCOD With headlights fOr hgh- To attain these. objects and such further ob- Way, roadway and other forms f illumination. jects as appear herein 0r may beV hereinafter My invelltiOn has fOr an Object the provision pointed out, I make reference to the accomof a projection device of utility for illumination vpanying drawings forming a' part hereof, in in connection with headlights and more particwhich 'f ularly utility in connection with my prior ap- Figure 1 is a sectional'view in side elevation DlieatiOnS ,Serial N0. 261,004 led Mareh 12, of my complete device in its preferred form; 1o 1928, now Patent No. 1,883,359, serial No. 335,875 Figure 2 is a front elevatiun of Figure 1; 10

led January 29, 1929, now Patent No. 1,883,360 Figure 3 is an enlarged detail of the projectand Serial No. 335,876 led January 29, 1929, ing and converging system;

now Patent No. 1,883,361 for Headlights for pro- Figure 4 is an enlarged detail .of an incanviding apparatus for projecting a converged descent bulb;

beam. Still more particularly it is contemplated Figure 5 is an enlarged detail of another em- 15 by my invention to provide a projection system bodiment of my invention; having utility in my inventions disclosed in my Figure 6 is a front elevation thereof; aforementioned applications, servingas a means` Figure 7 is a longitudinal sectional view of for providing a converging beam of light whereanother embodiment of my invention.

by it may be controlled in accordance with the Making reference to the drawings, in the pre- 20 projection system to provide maximum eiciency ferred form of my invention I provide a proand illumination and enhance the. qualities of jection system in the form of a. headlight I0, my prior inventions so far as elimination of having a main housing II. Interiorly disposed glare concerned, and to provide a headlight is a primary reector I2, preferably of ellipsoiwhose rays are so. controlled as to have proper dal configuration. At the optical axis of the v25 road distribution and discernibility behind the reflector, through an orice I3, there is disposed source of illumination by an approaching oban incandescent bulb I4, the stem or base thereserver. of I5a being located in the socket I5 which in Still further objects of my invention reside in turn is adapted to pass through the orifice I3.

the provision of an incandescent bulb or lamp The incandescent bulb or lamp just described .30 useful in connection with a projection system l has a tightly 'coiled filament I6.. -The assembly forA projecting a beam of lightin a direction most is so constructed that the filament of the lamp valuable for illumination purposes and for inis arranged to be disposed at'the primary focus creasing the eiliciency ofthe incandescent elef1 of the ellipsoidal reflector. 'I'he secondary ment so far as the dimensional characteristics focus f2 of the ellipsoidal reiiector is 'disposed 35 of the lamp are concerned. i to be within the housing II. I

Still further objects of my invention reside in Adjacent this secondary focus there is disthe provision of a projection system inY which posed a frusta-conical member I1,. having its e light from an incandescent source includes smaller opening I8 substantially concentric with 40 a reflective system, combined with directly prothe optical axis O O and its larger opening I9 40 jected rays from the. incandescent source, with substantially eccentric .with the optical axis maximum rays of light projected Without reec- O O.` In its preferred form it. will be undertion and the reected rays projected within a stood that the frusto-conical member'I'I is preusable angle, with the minimum amount of referably one in which the vertex thereof is preection, toAthereby provide aprojection system ferably oblique tothe optical axis. 45 of high efficiency. 7 Positioned at the mouth of the orifice I8, I pro- Still further objects -of my invention reside in vide a lens 20, preferably a plano-convexo rlens the provision of a projection system and an of the character which will converge' the rays .incandescent lamp for use therewith in which projected, thereon in 'amanner which will apthe directly projected rays are utilized for imaxipear more v.clearly as this description proceeds. 50 mum illumination and all normally uncontrolled At the orifice I9, I position a' second lens 2|.l or umerlected rays are utilized to the maximum This lens may also be of the plano-convexo type eiciency for conservation of the intensity of or one of the type carrying out the features emlight and for the provision of a projection sysbodied in my aforementioned application or that tem in which glare is reduced to the minimum led on even date herewith Serial No'. 626,785. 55-

- within the housing II so that its outermost portion is suspended within the housing, whereasr The frusto-conical member I1 is supported its innermost portion may be suspended upon an opaque wall.` Preferably, however, a spider 22, formed of three radiating arms, is utilized.

The incandescent lamp Ill, previously referred to, has its envelope formed from the base thereof, with a substantially spherical clear glass section 23. The frontal portion, disposed'in front of the filament I6 is formed with a frusto-conical extension 24, with the base adjacent the lilament and the apex 26 disposed away from it. The walls of the4 frusto-conically formed section of the envelope are mirrored between the points 25 and 26, leaving the area 2 adjacent the apex clear. The mirrored section 24 previously referred to is disposed to receive the rays emitted from the incandescent filament which would not strike within the confines of the primary reflector I2 as outlined by the angle PfP. Thus the primary reflector I2 encompasses the major portion of the rays emitted by the incandescent source I6 within the usable angle and the mirrored section 24 formed on the frusto-conical portion of the envelope of the incandescent lamp serves to control any direct diverging rays outside the usable angle and which would fall within the angle Pf'P and ordinarily uncontrolled by the primary reflector I2.

The slope of the frusto-conical mirrored section formed on the envelope of the incandescent lamp is s uch as to reflect the rays in a direction away from the primary reflector I2 and to prevent any reflection backward upon the primary reflector, Preferably the slope of this mirrored section 24 formed on the frusto-conical section of the envelope vis lsuch as to converge the reected rays through the clear section 2'!- of the envelope and adjacent the point in the focal area f2.- The preferred slope of the frusto-coni-J cally formed section 24 of the envelope above referred to is a cone formed by drawing a line from the focal point f2 substantially tangent tov the spherical portion 23 of the lamp I4.

The size of the clear portion 21 is preferably such that directly projected rays from the light source are conned to within limited small .angles such as the area of -the lens 20 in the embodiment referred to in Figure 1.

It will be observed that section 24 above described, will, under certain conditions, converge the rays reflected from the mirrored surface thereof at va point between the primary focus f1 and f2. However, this, for certain purposes contemplated by me, is desirable in that amore diffused beam is impinged upon.

the lens 20 adjacent the focal area.

optical axis will serve to be reflected downwardly The rays projected beyond the lens 20 will proceed outwardly to the frusto-conical reflector I1 below the optical axis O--O, without modillcation. 'I'hose rays of light diverging above the below the optical axis upon impinging uponthe upper surface of the conical reflector. I1, which upper interior surface substantially entirely above the optical axis, is formed internally with a mirrored reflective surface.

The modification of the M point is in accordance witl my aforementioned pending applications and theV emission of the beam through the lens 2| is dependent upon the character of the lens positioned at that point.

It will thus be observed that the. .character of light projected upon the lens 20 includes theconthe frustoconical beam beyond., this centrated-light emitted from the source I6 and obtained for substantially the major spherical angle by conversion to the point adjacent the focal area f2.- A portion of the light emitted is directly projected upon the aperture I8, at which point the lens 20 is positioned and also includes a portion forwardly projected adjacent this point by reflection from the frusto-conically formed reflective surface 24 formed on the envelope of the incandescent lamp.

The form of the frusto-conically. formed mirrored section 24formed preferably upon the envelope of the incandescent lamp and from the bulb itself,v` permits of projection of light from -the primary reflector I2, with maximum effectiveness in that the mirrored portion formed on the envelopeof the incandescent lamp does not in any way interfere with the usable beam walls of the bulb. 'I'he arrangement of the parts as described prevents the diffusion and' loss of light from the" source I6, which would ordinarily strike the primary reflector I2, and assuring that all forwardly projecting rays which would fall. outside the focal area are forwardly projected to within the region about the-optical axis encompassed by the lens 20. Furthermore, all forwardly projectedl rays are transmitted with minimum losses due to internal reflection.

In Figure 6 the incandescent lamp itself has been disclosed. In this construction, I usean incandescent bulb 23a of spherical or slightly ellipsoidal contour. Mounted uponthe forward portion of the envelope 23a and positioned to be concentric with the passing through the base I-5 a, there is provided a frusto-conical sleeve 24a, held in this position by straps 24h, the opposite ends vof which straps are soldered to the base I5a and the sleeve 24a to rigidly hold the sleeve 24a in position. The slope of the frusto-conical sleeve 24a is substantially identical with the portion 24o! the longitudinal axis O-O' j embodiment previously described and the en- A larged end 25a engages the bulb 23a and the smallend 26a is open at 21a or formed with a llens in accordance with an embodiment to be 'hereinafter described.

-in an assembly shown in Figure 3. In this assembly the reflector I2c may be an ellipsoidal reflector where used in a general assembly as in the preferred use described, or it may be other forms of reflectors such as a parabolic reflector, spherical reflector, or combinations thereof, and other .surfaces of reflective character known in the industries for illumination purposes in headlight projection systems, or optical projection systems of all kinds, such as for home moving picture machines, etc. In suchA embodiments as shown in Figure 3, the beam of light is converged adjacent the focal area f? of a film M or the objective of a lens system of such projection system.- l

Where the reflector I2c is a parabolic reector for transmitting a substantially parallel beam- 75 of light, the beam along the axial line o o' will be intensified for distant illumination with minamount of rays uncontrolled for such light as would I2C.

The incandescent lamp illustrated in detail not directly impinge upon the reilector vin Figure 4 and now just described in referring to Figure 6 in ay be used in the combination shown in Figure 1, with the utility attributed to this combined assembly or may be utilized with the standard form of headlight of the vgeneral parabolic type, with considerable effectiveness.

In such assembly, the embodiment just described and illustrated in Figure 6 is positioned within the normal socket provided in the headlight so that the lament I6 is positioned at the focal point of this reflector, permitting the clear portion of the envelope of the lamp to transmit the major portion of the light from the lament rearwardly upon the primary or parabolic 'reector where this is used.' Those rays which do not impinge upon the primary or the main -parabolic reector are encompassed by the frusto-conical reflector either formed upon the Vvincandescent bulb or envelope as in the embod'- iment shown in Figure 4 or upon the sleeve 2.a,

in accordance with the embodimentl shown in Figure 6.

Thus only a small portion of the rays directly emitted and immediately surrounding the optical am's will-be uncontrolled and projected through Ythe clear portion 21a, while the rapidly diverging rays normally directly emitted will fall upon beam exceedingly useful for distant illumination.

- In Figure? I have illustrated a still further embodiment of my invention, in which I show a c headlight comprising a housing I0, within which is mounted a primary reflector- Il, preferably of ellipsoidal character, or a distorted parabol id arranged to converge the light impinged upon it at a focal area within the headlight. .The re-` ilector ll is formed with an orifice 42, through which extends the socket 43, of an incandescent bulb u. The filament l! is preferably of the und t and is 'arran ed to o rate closely wo ype g pe condlut 5|, ln accordance with the principles andfor the desirable purposes referred Jto in my 55 preferably within a gas lled atmosphere. The filament 45 is disposed at the primary focusl f' of the reflector 4I, the secondary focus being at the point j within the headlight.'

Mounted upon the envelope of the' incandescent bulb M is a frusto-conical sleeveG, formed interior-ly thereof with a mirrored' reflective surface. 'Ihe frusto-conical sleeve 46 is positioned y in the assembly just described and is of a slope substantially in accordance with the embodiments previouslyreferred to and this may be either integral with the Yenvelope of the incandescent bulb M, in which event Vthe glass is silvered to have the interior of the sleeve mirrored, or it may be mounted exteriorly of a spherical or slightly ellipsoidal bulb, in' accordance v'with the construction illustrated in Fig. 6. In this embodiment, however, I prefer,to 'mount at the restricted opening 41, a lens 48.` This lens has its central portion formed with a planoplano section 49. The remainder-of the lens to the edges of the sleeve in which it is mounted and concentrically with the center 40 is(plano-d concavo 50, serving to diverge the rays impinged 'f directly upon it from the nlament 4s orv that emitted by reflection from the rellected walls of the frusta-conical sleeve The curvature 5 of the plano-concave lens is such to substantially render the rays emitted nearer to parallelism or to a converging p oint adjacent 4the focalplane f2. At `this point I. position a frustoconical reflective conduit 5l. 'I'he small `end 52 10 of the frusto-conical reective conduit 5I is positioned substantially concentric with the optical axis O O'. The enlarged end opening 53 is substantially eccentric withrthe optical axis ,0,-02 'I'he upperv interior surface 54 for sub- 15 I stantially the entire portion above the optical axis is formed with a'mirrored reective surface interiorly thereof. l

The frusto-conical reflective conduit 5I is'supportedwitnln ,the'housing at its lmall end by 2 an opaque partition member 55. However, this may be a spider. 'Ehe remainder of thev housingI may be constructed to conform 'to the opening 53 and thereby serve to support this end of the frusta-conical reflective conduit. -At the re-` 25 stricted opening 52' of the frusta-conicalv reflective conduit f5! there is .positioned'a lens 56.

.This lens may be of" the 4plano-convex type.

Preferably, however, it is onewhich is formed with a plano-plano centerSLVthe opening being 3 0 slightly, larger than the plano-plano center 49 o of the-first lens 41 aforementioned. The convex portions thereofV may, however, be groundfn accordance with the preferred embodiment of. this lens. as disclosed in my copending application Sf rial No. 626,785 for 'a lens construction illed on equal date herewith. d

The enlarged opening of the conical reflective conduit 5I -is provided with a lens 59. This may also ,be of the plano-convex type or ,may be fonned with a plano-plano centerdandfwith refractive diverging prisms in accordance with predetermined desired road distributing characteristics. Y 45 By lthe construction described, it will be observed that conc'entxicallyI wi the optical axis, an extremely intense beamgw'ill 'be projected .which is definitely .controlled and tbatsubstan- A tially 4the entirel spherical angle .ofr the light 50 emanating from the lament 45 will be otherwise forwardly projected adjacent the focal plane f2 forprojection Linto the conical reile'ctive" aforementioned prior filed applications.

f Thus, by my invention, maximum intensity of i light is obtained; with denit control'. Also internal reflection of -the projection system is avoided preventing jany uncontrolled rays from/ 6,0- being projected due toaberrational effectsy and A rounding the vmajor spherical angle about said 70` lament upto a mirror portion forwardly thereof, the portion of said envelope intermediate to said clear sections-being formed-with a con f centrically arranged mirrored, reflective surface disposed at an acute angle forwardly directingfl` ,the rays emanated from said lament and impinging on said reflective surface;

2. Ina light projection apparatus, including a housing anda primary condensing reflector rounding the major spherical angle about said filament up to a mirrored portion forwardly thereof, the portion of said envelope intermediate to said clear sections being formed with a con' centrically arranged mirrored reflective surface disposed at an acute angle forwardly directing the rays emanating from the lament and impinging on said reflective surface.

BRAUDDUS BROCK FORTNEY. 

